Every year, several thousand accidents that are caused by wrong-way drivers (also called “ghost drivers”) occur in Germany alone—especially on highways. The consequences of a collision with a wrong-way driver are even nowadays mostly life-threatening if not fatal. Nevertheless, there are currently no active safety measures or direct warning systems for traffic participants who are directly within the danger area and affected thereby. It is true that traffic information within the transmission area is provided by the car radio via TMC (Traffic Message Channel). However, the latency of the traffic service is much too high on account of the manual alerting routes. Although the patent literature makes several suggestions, these have so far not been put into practice—above all for reasons of costs. For instance, DE 101 26 548 A1 discloses a driving-direction monitoring system in which transmitters are provided at the roadway side for emitting signals which are to be processed at least into warning signals by vehicle-mounted receivers or by a vehicle-mounted central data processing device communicating with said receivers. However, it would be very troublesome to put this concept into practice since all vehicles would have to be equipped with corresponding receiving and processing units. Moreover, in the case of intended wrong-way driving, wrong-way travels cannot be prevented by outputting a signal to the wrong-way driver. Therefore, in the case of wrong-way driving DE 101 26 548 A1 suggests manipulations with the on-board electronic system, the fuel supply and/or the ignition coil and/or the engine control and/or the brakes of the respective vehicle, which would raise the investment costs even more.